If you had a multi-filament printer, I wonder if you could print the nylon bearing within another plastic piece (e.g. the part that holds the spindle to the z-axis)? That would would be pretty cool and would also save assembly time.

Are you looking at this for a 3D printer or for your CNC? If you are looking at it for a 3D printer, have you looked at the RAMPS 1.4 boards? I like their modular design over a fully integrated board for the simple fact that if a part dies, you are only replacing the one part and not an entire board. This make repairs cheaper if something goes wrong.

@NeverDie I have one more question of measurements on your CNC. If you look at the pic, can you tell me the measurements of the red and blue arrows on your machine? I have some idea of how tall I want my bracket for the red arrow area, but you were mentioning that you wish you had more travel in that area and I am curious if I have enough room.

Perhaps slightly off topic but I wanted to share very interesting youtube channel of FRANK from Germany link text who's been working on a PCB pick and place module along with a CNC tool changer in the video above.

Very inginious, and clever work if you've not come accross his videos and work yet.!

PCB pick and place module along with a CNC tool changer in the video above.

Imho, it's certainly a fun project.. but I think you can go faster by hand
Only a thousands more expensive machine will be faster for assembling, and they are more precise, have a lot more features (cam driven features, more feeders etc.).

Pick And Place is not plug and play at all there is lot of calibration, preparation. So it's useful and save time, only if you plan volume production. This is why there is often fees when you ask for a pcba, they spend time for calibrating each new board, parts in database etc.

There are multiple different diy pnp, most of them are slow, not enough precise for <0402 etc..
If it's for 0603 size with some dfn, low volume, you don't need this kind of investments I think.. but if you want to tinker it's fun I imagine.

For example, if I remember well, someone said he can assemble an easypcb in 30mn, trhough hole. Good but that's the time I need to get assembled&soldered one of my compact smd multisensors boards, no PNP, no handsoldering..
PNP is just for placing, it won't fix test, soldering shorts etc, that still need some agility

No need of a solder paster dispenser, I use stencils. I like freedom for placing parts, but you can also build a simple manual pick&place in case you shake when placing (no shaking here). With a good magnifier, easy! (I have a big one like dentists, + another one with a cam). Finally, the reflow oven cook it. When I need a repair/reflow -> flux + hot air or fine solder tip. Well organized, you're faster like that. Not the same, if you want to assemble 50 boards, agreed.

So, I've no real xp on PNP, but I'm not new at assembling smd boards. Saying this because I already digged in forums, diy builds, reviews, as I need to invest in a cnc router, and PNP this year. and I'm lucky I can talk with local professionals.. I always "try" to get a good ratio between the need/time/ROI . I'll build the cnc router, but I'll buy the PNP. there are a few interesting but it's still a few thousands dollars.

@neverdie I saw this stepcraft automatic tool changer, its nice, but the design aproach of Franks is really novel, and way cheapper, simple ingenious. But my skill level is much lower, so I could be wrong

@neverdie you mean the tool changer, yes he has a blog and git pages where he shares. Its neccessary to speed control with current limiting breaking the spindle, which he's done via cheap ebay motor controller and arduino. Same goes for the spindle locking mechanism powered by a servo. and the CNC software..

@neverdie I'm gathering parts to make the same 3d printer with the carbon rods. I understood the weight reduction on the moving parts with carbon rods was the reason to go for them. And with the light 3d printer head that model can print much faster because of the stability and lightness. Which perhaps dosn't apply for the 2418 cnc ?

@neverdie Wall thickness as well as the material characteristics determine tube stiffness, comparison on the modulus alone is misleading.
As well as carrying the load, the section must also support it's own weight, one aspect where carbon fibre will out-perform steel.

What's the best way to check the RPM on my spindle? From looking at similar spindles on-line, I think it might be as low as 6000RPM at 24v.
So.... if I upgraded to a spindle that could go, say, 12000RPM, could I simply increase my feedrate by 2x and be done twice as fast?

@neverdie Bluntly no idea whatsoever, I was merely highlighting the incorrect interpretation.
There is no magic bullet, that's why engineers are still in business, the analysis can be complex.
Were I looking at such a project it would to the lightest and stiffest complex alloy extrusions I would be focusing attention, and figuring out how best to combine them in a frame with minimal deformation.
Complex alloy extrusions are cheap sections with known quantified parameters and constraints, composites are relatively new, and their interconnections are less well understood than with conventional materials. unless you work for Lotus or Ferrari...

I actually haven't had much trouble with vibration, so I can't really speak to that. The problems I've had have mostly been around runout, occasional arcing in the old spindle causing enough EMI to reset the microcontroller, Z-Axis backlash, the super-slow milling speeds necessary when spinning at such a low RPM, copper flakes everywhere, etc. Having the faster (and, maybe unfortunately, heavier) brushless spindle has been great for all of those things.

I happened to notice you looking into tool changers; if you're using bCNC, you might not have noticed the tool change workflow -- it's actually pretty elegant and will automatically re-zero your Z-Axis. It does require having a limit switch on at least the top of that axis, though. I used to hate tool changes given how tedious they were, but now they're pretty effortless.

Seems like most DC CNC spindles can do no more than 12,000RPM (if that). Which leads me to wonder: would replacing a spindle with a dremel be advisable? A dremel has an adjustable range of 5,000 to 35,000RPM.

It only goes to 12,000RPM, but I may be willing to trade speed for quiet. I can only assume that the 60000RPM unit isn't very quiet. Not at all sure how the brushless motor would compare. Possibly quieter?

I upgraded my CNC LoRa remote monitor into a more universal remote control by making it more compact and giving it 14 buttons:

It turns out I can count the number of auto-leveling probes performed, in real time, because the total CNC current briefly drops to almost zero each time the probe makes contact with the PCB. Thus, this gives me a way of tracking auto-leveling progress remotely.

I'm also looking for a good spindle so thanks for the links and comments.

Thought I'd share this link text. Its the 30A High Power Single way H-bridge DC Motor Driver Module. That "Frank From Germany" found and is using as part of his tool changing, along with a current sensor so he can brake, reverse and control speed on his tool changer, via arduino, to make it all work.

@neverdie Thanks thats what I thought, but I'm confused about the voltage range of some of the spindles. They use variable DC voltage to regulate speed ? I don't thinks so, they use PWM at any voltage I provide it with, no ?

So the V range specified on DC spindle is just what it can be driven at, and its the PWM which actually controls the speed ? Is this right ?

@rfm69 I believe so, at least for brush motors. For brushless, I get the impression the motors are missing the electronics which tell them when to alternate their currents internally, so (it appears) you need a special driver to make them move at all. I'm not sure how, or even if, PWM fits into that. Maybe motor speed is all managed entirely through the brushless controller, and all the brushless controller wants as input is pure DC?

In any case, I suspect that greater control over the speed of the spindle will lead to greater control over vibration as well. i.e. select a speed where there is less resonance/vibration of the pcb/spindle. Using an accelerometer to measure vibration, perhaps that could even be made somewhat automatic.

Alternatively, a trick I've seen used is to continuously vary the RPM over some range, so that the amount of time spent dwelling at the resonance frequency is reduced. That would also be easier to implement.

I imagine that either method might also lead to a generally quieter machine, which, IMHO, is generally desirable.

On the other hand, etching PCB's shouldn't be as taxing as full-on CNC work, so I'm not yet convinced it wouldn't work for etching PCB's. I think it's worth a try. If 35,000RPM turned out to be a great speed to etch at, then I'd be motivated to upgrade further and try 60,000RPM.

Would there be more runout at those higher speeds? On the one hand, the spindle is possibly more precise to begin with. On the other hand, at those rotational speeds, the bit might want to bend just from the centrifugal forces on it, unless it was perfectly balanced. Most etching bits don't even look perfectly balanced though....

Dc aka brushed spindles run on constant (dc) current&voltage. They have some limits. Power it under minimum voltage and they will stall (stop rotating) and only one coil will be energised, heat up and blow. Over maximum voltage they overheat and burn (logically).
You can use a constant voltage source or pwm a maximum voltage since the electro-mechanical inertia will act as an integrator and smooth out the pwm pulses asuming pwm frequency is high enough. The driving circuit can be as simple as a high power FET or a complex constant dc voltage source. You control that circuit via a low power pwm or voltage signal. Pwm can be easily converted to dc by a low-pass RC filter.

Brushless motors NEED a driver, same as steppers, since phases must be shifted in syncronisation to shaft speed and position. The control of the driving circuit is the same pwm or dc voltage talk as above.

@executivul Thanks makes sense and I just started to read simular explaination in other places, but yours helped.

How about rpm ? Is it generally considered that higher RPM is better, or at least not being limited by a low speed ? I've seen 1 300w spindle rated at 60,000rpm would this be better than a higher power slower spindle ?

@NeverDie I use my 60k rpm spindle at 30-40k rpm most of the time. I manualy crank the vfd pot to max rpm, then slowly start lowering taking notes where the lowest harmonic resonance points are, then chose the highest acceptable one. Eg 100% rpm high noise, 94% rpm low noise, 93-84% rpm noise again, 83%rpm even lower noise, 82-xxx% noise again. I chose 83%. Most Vcarve milling bits are rated to 40k rpm anyways. This speed / resonance tuning must be done after every tool change, even a slight tightening of the tool a bit more can change balancing.
IMHO 24k rpm are enough for up to 1000mm/min pcb milling.

@executivul Which 60K rpm spindle is it that you are using? Are you generally happy with it, even if you tend to run in the 30-40K rpm range most of the time? i.e. would you buy it again, or would you maybe get something different?

@rfm69 the honest answear: "It depends!"
I've had much better luck at higher rpm. I've even posted a gcode to determine the best feed/rpm in this thread.
To mathematically know for sure you would need a few hundred thousand dollars worth of equipment, engraving pcbs is not milling, so chipload calculators won't work. Lower rpm rips the copper leaving rough edges, too high of a rpm increases runout. As I've said IMHO 24-30k rpm is enough for our machines, you need a far better, stiffer frame, servos instead of steppers and a very good controller board to be able to go over 1000mm/s (400in/s).

Remember, as in stepper's case, running a spindle at 50% of max rpm yelds far less than 50% of power, maybe as low as 10%. Going under 50% you get as low as 3-5% of max rated power. For pcbs that's no biggie, but for anything else... And you can't mill wood or metals at 60k rpm because of the feedrate needed to keep the chipload and the cooling needed not to burn the tool and stock.

I've said it before and I'll say it again. This is a low cost DC motor that has a ER collet adapter attached to it. It is not a CNC spindle that incorporates the tool holder right into spindle with a minimum of stick out from the housing.
There is no bearing preload and the bearings are low cost bearings that have a lot of slop in them.
A bent motor shaft of just a couple of thou will cause a large run out at the tool.

I notice that a lot of the available spindles are exactly that: a motor with an ER11 collet attached. So, the stickout is going to be greater. I haven't yet tried to find a proper CNC spindle like what he describes, where there's minimal stickout. In a perfect world, it sounds like that may be the way to go though.

@neverdie any half decent watercooled spindle should have the ER collet holder integrated. My 60k one has an ER8 and the default DC that came with the machine an ER11. Bought some ER high precision collets from ali, and some precision nuts and things got even better.

You can tell by the listing title or after doing some tests either with a dial gauge or by running it and listening.

Beware 2: diameter, my 3040 came with 53mm spindle holder, single piece with z carriage, so the 48mm only needed a 3d printed sleeve, but to add a 63mm or 80mm diameter spindle some heavy mods were needed so that's one of the reasons I didn't go with them

Beware 3: weight, the frame must support it without complaining, z drop, backlash or whatever

My 10^5*2c: get a 6040cnc with supported rails and a 0.8-2kw water cooled spindle, will serve you good for anything from pcb to alu or bronze milling, even some light steel work on the 2kw one and will save you a lot of hassle in the long run.

LE. 3020 and 3040 don't have supported rails and many don't even have ballscrews

And if you're really anal about it get the ballscrew frame only from rattm on ebay, a set of hybrid servos, a spindle+vfd+pump, a controller of your choice and you can say you have the best tool in the entry class of router cncs.

@neverdie please search for the 6040 frame only from "rattm motor", it's not stated I believe but you can clearly see in the photos with the bed beams removed that y rails are supported. X are not, but they are high diameter and pretty stiff for 40cm wide span.

Imho wheels on rails will never ever ever be as stiff and have less flex than the lousiest linear bearing. Wheels on rails are for printers and lasers.

@neverdie it might be better than a rigid x axis aluminium profile dangling on some wheels all together. Then comes the profile joining piece dance.
On the cnczone forums people go like: linear rails are the best, round bars are good, wheels on rails are for toys. That is for normal milling on a small machine. These things are routers by the way, real mills are taig style and are small size and meant for steel and heavy metal milling (no pun intended). For wood, plastic, soft stuff it might be acceptable though.
For pcbs you need high precision, flatness, high rpm etc.
For wood you need large size, think of table or door pieces. Tolerances are not so tight. You won't go like: look! Your door engraving is 0.1mm off in that corner!
For metal you need precision, high rigidity and power at lower spindle speed.

@neverdie you must use a chipload calculator according to your spindle power at requested rpm, tool diameter and tool profile. Stock can be as thick as you want, the machine has about 100mm of z travel, you mill in multiple passes anyway so milling depth per pass is based on the results from calculator, experience or many broken tools.

I think a better way to do it would be to directly couple the encoder to a dual-shaft stepper motor, but that would, of course, mean purchasing a new stepper motor. Nonetheless, these small stepper's are pretty cheap.

The other way to do it with the existing single shaft stepper but without a belt might be to use a magnetic encoder, but I can't say that I've tried that, so I'm not sure how hard the retrofit would be.

Also, I guess the main point in doing this would be to hotrod your CNC, to make it move faster without skipping steps. i.e. you probably don't absolutely need to hotrod your CNC.

I think a better way to do it would be to directly couple the encoder to a dual-shaft stepper motor, but that would, of course, mean purchasing a new stepper motor. Nonetheless, these small stepper's are pretty cheap.

I never looked, but do they make a dual notched pulley? Then you would only need to buy a pulley vs an entire stepper.

@rfm69 Almost always just PCBs. Maybe sometimes some acrylic, but nothing very solid, if that's what you're asking. Those little 1610 CNCs have so many plastic parts, that I'm not sure it'd perform very well cutting anything much harder than plastic.

@neverdie Yes; brushless motors are for sure more technically complex than brushed, and usually require an external driver. Most of the time those drivers have inputs allowing you to control the speed via PWM or an analog voltage.

Adapting the 1610's woodpecker board to supply that PWM speed control signal to an external driver is super easy -- I can show you a photo of what I did to mine if it'd help.

@neverdie And finding a good tool at an affordable price is a challenge. Specialised machines do a s specific job better than general purpose ones, but only do that job. Professional machines do a better job at a higher price tag. We are just poor hobbyists

I'm so happy with my $50 UT61E, what a great multimeter, of course I would rather have a HP 8.5 digit one any day but I'd rather spend that money on a holiday or something since I don't need that 0.0001uV precision anyway, at 1V a 3V bat is as empty as a 0.9999999987V one if you get my point. Too many times I've spent a fortune for professional tools which I don't use/need so I tend to get what I need + a small margin, for eg I got a huge DSLR and lenses, used a few times, great photos, but lately, guess what, I tend to use my phone for taking photos 99.9% of the time, the camera backpack is just too heavy to carry arround .

Get a 3d printer, get a 3040/6040 cnc, get a 40/50W laser, get a lathe if you have space for it, maybe get a vertical mill for metal parts and you'll have a maker space of your own, as long as you won't start manufacturing space ships ebay tool tolerances will be ok.

I did some more reading about CNC'ing aluminum, and it's being claimed that virtually any CNC machine can cut aluminum, provided it uses the right depth of cut and speeds and feeds. i.e. it may simply take a lot longer than you would prefer if your machine isn't already super rigid. If that's true, I can probably live with that.

Meanwhile, it has been suggested that using PID might improve things. There's SuperPID for AC powered spindles and I'm not sure what for DC powered spindles. Regardless, I'll need to sense the RPM of the spindle, or it won't work, so that's now on the critical path. I think I'll try a spinning magnet and a hall sensor to sense the RPM.

Does the controller that comes with your motor allow you to set the RPM of the motor, or does it just set the voltage? If it knows RPM and can act like a PID (i.e. adapts to maintain the target RPM even under varying loads), then it would be very attractive.

First, I confirmed that the motor is, indeed, being powered at 24VDC using pulse width modulation from the WoodPecker. As an experiment, I tried powering it directly from my lab bench power supply at different voltages, and it definitely runs smoother that way rather than relying on PWM.

Second, when I ran it at very low speeds, I could tell visually that the spindle runout was attrocious. I think this is a big contributing factor to vibration, audible noise, and probably tearing in the copper of the PCB. It may be that the large stick-out of the ER11 is a contributing factor.

@neverdie Yes, it does. There are a variety of ways of controlling the one I bought, and you can easily configure which method is in use. I think this one has three different options -- controlling RPM via an analog voltage, controlling RPM via PWM, and controlling RPM via a knob on the controller. I use PWM, but you'll probably always want to be at full speed when milling PCBs, so I'd bet just using the knob would be fine.

@neverdie Yes, it does. There are a variety of ways of controlling the one I bought, and you can easily configure which method is in use. I think this one has three different options -- controlling RPM via an analog voltage, controlling RPM via PWM, and controlling RPM via a knob on the controller. I use PWM, but you'll probably always want to be at full speed when milling PCBs, so I'd bet just using the knob would be fine.

So, during deeper cuts, the controller responds by giving the spindle more oomph to maintain the specific RPM you set? That's the key question.